And he is 95 years old:

Former West Virginia Secretary of State Ken Hechler, a nonagenarian Democrat who has held office in the state on and off since 1958, has filed to run in his party’s Senate primary against Gov. Joe Manchin.
The West Virginia secretary of state’s office confirmed that Hechler filed the appropriate paperwork by fax and paid the $1,740 fee to enter the special election race for the late Sen. Robert Byrd’s seat.
At 95, Hechler is three years old than Byrd was at the time of his death on June 28. . . Hechler served in Congress from 1959 until 1977, and then held office as secretary of state for 16 years beginning in the mid-1980s. He mounted an unsuccessful campaign for Congress in 2000 and lost a comeback bid for secretary of state in 2004.

Meanwhile, on the GOP side:

Troy Berman, executive director of the West Virginia Republican Party, said Capito’s decision “shakes up the race” and that he has been fielding calls all morning from people interested in running on the Republican ticket.
“It looks as if Republicans will have a robust primary to select their nominee,” he said. The filing deadline for candidates is Friday and a primary will be held Aug. 28, a Saturday. John Raese, a former state Republican Party chairman who lost to Byrd in 2006, has said he’s considering running.